If you are within 0.7 ~ 1m (28 ~ 39.3 in) from the outside tailgate handle, with your smart key in possession, the tailgate will unlock and open when you press the tailgate handle switch.
The hazard warning lights will blink twice to indicate that the tailgate is unlocked.
Also, once the tailgate is opened and then closed, the tailgate will lock automatically.
Kia Niro (DE HEV) Owners Manual: VSM operation
When the VSM is operating:
ESC (Electronic Stability Control) ()
light will blink.
The steering wheel may be controlled.
When the vehicle stability management is operating properly, you can feel a slight
pulsation in the vehicle. This is only the effect of brake control and indicates
...
Kia Niro 2017 (DE HEV) Service Manual: Hood Latch Release Handle Components and components location
Component Location
1. Hood latch release handle
...